In Testing the Hypotheses
H0: μ = 20
HA: μ $\neq$

In testing the hypotheses
H0: μ = 20
HA: μ < 20 $\neq$
the following information was given: $\sigma$ = 8.1, n = 100, $\bar { X }$ = 18.1, α = 0.025.
a. Calculate the value of the test statistic.
b. Set up the rejection region.
c. Determine the p-value.
d. Interpret the result.